Periodic Table Introduction Flashcards
What are the vertical columns on the periodic table called?
The vertical columns are called groups and are numbered 1 to 18.
How are the elements arranged in the periodic table?
The elements are arranged in order of increasing atomic number across each period, and a new period begins after each group 18 element.
Where are the atomic masses located on the periodic table?
The atomic masses are given (generally to four significant figures) below each chemical symbol. While the atomic mass usually increases with atomic number, you can see exceptions: Te and I, and Ar and Ka as well as Co and Ni. While the isotopic composition and, therefore, the atomic masses of most elements are well established, there are some unstable elements that undergo spontaneous radioactive decay. Given that the isotopic composition of such elements cannot be known, it is usual to simply quote the mass number of the longest lived isotope of the element, and these are given in parentheses in the periodic table.
Why are elements 56-72 and 88-104 not located in the periodic table the same as the other elements, but given below the table instead?
The elements from 57 to 71 are called the lanthanoids (or, less commonly, the rare earth elements). Elements 89 to 103 are called the actinoids. The lanthanoids and actinoids are generally situated below the rest of the periodic table, simply to save space and to make the table easier to read; note that the lanthanoid and actinoid elements are chemically distinct from the rest of the elements in the periodic table, and do not belong to any of the groups 1 to 18.
The lanthanoids and actinoids are sometimes called the f-block elements, and a similar terminology is also used elsewhere in the table; elements in groups 1 and 2 are called the s-block elements, elements in groups 3 to 12 are called the d-block elements, and elements in groups 13 to 18 are called the p-block elements. As we will see, s, p, d and f refer to orbitals, particular regions in space in the atom where electrons have a high probability of being found. The d-block elements are also called transition metals.
What are the group names in the periodic table?
Individual groups within the periodic table are also known by particular names, although this practice is less prevalent than in the past. Group 1 elements are called alkali metals, group 2 elements are called alkaline earth metals, group 15 elements are called pnictogens, group 16 elements are called chalcogens, group 17 elements are called halogens and group 18 elements are called noble gases.
Of these, only the terms halogens and noble gases are in common usage.
What are the three categories that elements belong to in the periodic table?
All elements on the periodic table belong to one of three categories — metals, nonmetals and metalloids.
Metals are generally good conductors of heat and electricity, are malleable (can be beaten into a thin sheet) and ductile (can be drawn out into a wire), and have the usual metallic lustre. Elements that do not have these characteristics are called nonmetals, and the majority of these are gases at room temperature and pressure. The properties of metalloids lie somewhere between the metals and nonmetals. The most notable property of these elements is the fact that they tend to be semiconductors, and metalloids such as silicon, Si, and germanium, Ge, have therefore found wide use in silicon chips and transistors.
Note that the classification of the recently prepared elements 116, 117 and 118 is somewhat arbitrary, as weighable quantities of these have not yet been obtained.
What are the horizontal rows on the periodic table called?
The horizontal rows are called periods and are numbered 1 to 7.
